This invention relates to a locking device using a loop-shaped latch spring to be applied to a rectangular electronic connector (typically standardized in EIA-232D of EIA or Electronic Industries Association) whose size is of the order of ones mounted on a back of an electronic appliance, for example, a personal computer for connecting the computer to peripheral equipment, and more particularly an improvement of latch supports for latch springs of a connector.
First, requirements to such latch springs will be explained.
(1) In general, during shipment and transportation, connectors are piled with latch springs 20 in horizontal positions as shown in FIG. 8 to advantageously reduce spaces for piling. It is therefore required that the latch springs are stably stationary in the horizontal positions (P in FIG. 9). In FIGS. 8 and 9, the latch springs 20 are pivotally connected to a connector 10 at latch supports 30. PA1 (2) Moreover, connectors of this kind are often fixed to panels of appliances. In such case, the latch springs 20 are sometimes required to be stably stationary in vertical positions (Q in FIG. 9) owing to a requirement resulting from a relation to a mounting aperture 52 of the panel 50 as shown in FIG. 10. PA1 (3) In case of the latch springs being used as locking means for a connector, the latch springs 20 are in inclined positions as shown in FIG. 11 and need to be kept to prevent from rotating from the inclined positions to horizontal positions in order to facilitate engagement with a mating connector. PA1 (4) In order to secure the connector 10 to the panel 50 shown in FIG. 10, the latch springs 20 are manually forced to rotate toward the vertical positions with their free ends. In this case, it is preferable for saving steps of mounting process that after the latch springs have been rotated through certain angles before arriving at the vertical positions (Q in FIG. 9), the latch springs can rotate by themselves or automatically to the vertical positions without requiring further urging forces by hands. On the other hands, it is of course better that the latch springs are caused to be snugly positioned in the desired vertical positions without being rotated too far. In case of the latch spring being rotated too far, they must be returned into opposite directions. PA1 (5) The above requirements are summarized as follows.
In other words, the latch springs need to be maintained at inclined positions at a predetermined angle (R in FIG. 9).
1. The latch springs must be stably stationary in horizontal positions (P in FIG. 9). PA2 2. The latch springs must be stably stationary in vertical positions (Q in FIG. 9). PA2 3. The latch springs must be stably stationary in predetermined inclined positions (R in FIG. 9). PA2 4. The latch springs must be automatically forced to rotate from the horizontal positions P to the vertical positions Q, but must not be forced in movement from the vertical positions Q to the inclined positions R.
FIGS. 1a and 1b illustrate a latch spring of the prior art. The latch spring 20 has pivotal ends 24 which are inserted in half-cylindrical support portions 30. End faces of the support portions 30 on which the latch springs slide are flat and in parallel with sliding directions of the latch springs.
With such an arrangement, the latch springs 20 are not subjected to any automatic action to rotate toward the desired vertical positions during rotations and forces for restraining the latch springs 20 are only frictional forces which are uniform and caused in areas of the support portions 30 in which the latch springs 20 rotate.
In consideration of the above requirements, the latch springs 20 of the prior art do not fulfill the requirement (4), because they are not subjected to the automatic action. Moreover, the latch springs stop in inclined positions, but they are not particularly stably stationary in such positions in comparison with other inclined positions. Therefore, the latch springs of the prior art do not fulfill the requirement (3) either.
FIGS. 2a and 2b illustrate another latch spring of the prior art. With the latch spring, support portions 30 are formed with notches 31. Therefore, the latch spring 20 falls into the notches 31 at the midway of their rotations so that the latch spring 20 rests stably in inclined positions determined by the notches 31 of the support portions 30.
However, the latch spring 20 is not stably stationary in positions other than the inclined positions determined by the notches 31, because the latch spring 20 is always urged into the notches 31. Therefore, the latch springs 20 of the second prior art do not fulfill the requirements (1) and (2). Moreover, they of course do not fulfill the requirement (4).